Does Perl have reference type?

Q

✍: Guest

A

Yes. Perl can make a scalar or hash type reference by using backslash operator.
For example
$str = "here we go"; # a scalar variable
$strref = \$str; # a reference to a scalar

@array = (1..10); # an array
$arrayref = \@array; # a reference to an array
Note that the reference itself is a scalar.

2013-09-12, 2645👍, 0💬

How to read file into hash array ?
How to read file into hash array ? open(IN, "<name_file") or die "Couldn't open file for processing: $!"; while (<IN>) { chomp; $hash_table{$_} = 0; } close IN; print "$_ = $hash_table{$_}\n" foreach keys %hash_table; 2013-09-10, 2927👍, 0💬

How do I sort a hash by the hash value?
How do I sort a hash by the hash value? Here's a program that prints the contents of the grades hash, sorted numerically by the hash value: #!/usr/bin/perl -w # Help sort a hash by the hash 'value', not the 'key'. to highest). sub hashValueAscendingNum { $grades{$a} <=> $grades{$b}; } ... 2013-09-10, 2884👍, 0💬

If EXPR is an arbitrary expression, what is the difference between $Foo::{EXPR} and *{"Foo::".EXPR}?
If EXPR is an arbitrary expression, what is the difference between $Foo::{EXPR} and *{"Foo::".EXPR}? The second is disallowed under `use strict "refs"'. Dereferencing a string with *{"STR"} is disallowed under the refs stricture, although *{STR} would not be. This is similar in spirit to the way ${"... 2013-09-16, 2836👍, 0💬

How do I do < fill-in-the-blank > for each element in an array?
How do I do < fill-in-the-blank > for each element in an array? #!/usr/bin/perl -w @homeRunHitters = ('McGwire', 'Sosa', 'Maris', 'Ruth'); foreach (@homeRunHitters) { print "$_ hit a lot of home runs in one year\n"; } 2013-09-16, 2776👍, 0💬

How to dereference a reference?
How to dereference a reference? There are a number of ways to dereference a reference. Using two dollar signs to dereference a scalar. $original = $$strref; Using @ sign to dereference an array. @list = @$arrayref; Similar for hashes. 2013-09-13, 2701👍, 0💬

How do you find the length of an array?
How do you find the length of an array? $@array 2013-09-11, 2666👍, 0💬

What value is returned by a lone `return;' statement?
What value is returned by a lone `return;' statement? The undefined value in scalar context, and the empty list value () in list context. This way functions that wish to return failure can just use a simple return without worrying about the context in which they were called. 2013-09-11, 2649👍, 0💬

Does Perl have reference type?
Does Perl have reference type? Yes. Perl can make a scalar or hash type reference by using backslash operator. For example $str = "here we go"; # a scalar variable $strref = \$str; # a reference to a scalar @array = (1..10); # an array $arrayref = \@array; # a reference to an array Note that the ref... 2013-09-12, 2646👍, 0💬

What's the difference between /^Foo/s and /^Foo/?
What's the difference between /^Foo/s and /^Foo/? The second would match Foo other than at the start of the record if $* were set. The deprecated $* flag does double duty, filling the roles of both /s and /m. By using /s, you suppress any settings of that spooky variable, and force your carets and d... 2013-09-12, 2609👍, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.